This invention relates to shackles and more particularly to handcuffs, and leg irons, with double-locking mechanisms.
Handcuffs, such as those shown in U.S. Pat. No. 4,509,346, issued to Szczepanek, typically have a pair of arcuate frame parts, known as a jaw and casing cheek, that are pivotally coupled to one another. A pawl-and-ratchet mechanism permits one-way rotational movement of the jaw as it pivots through the spaced apart arms or plates that form the cheek on the shackle casing. Teeth on the pawl ride over complementary ratchet teeth in the jaw, as the jaw rotates into the cheek, to lock the cuff around a person""s wrist. Spring pressure against the pawl is provided to prevent the jaw from backing off and unlocking the cuff.
This basic structure is improved by the addition of a slide bolt that overlays the pawl, inside the casing. When a small key end is pushed into a side channel of the casing, a separate drift pin carried in the channel moved against an end of the bolt. Continued pressure causes the bolt to slide so that an interference surface on the bolt then abuts the pawl. This surface blocks the pawl to prevent it from being depressed, and holds the pawl in place acting as a xe2x80x9cdouble lockxe2x80x9d. This double lock not only prevents the jaw from being picked open, but it also prevents over tightening of the cuff and possible injury to the person being cuffed. Slide bolts were thereafter further modified as, for example, illustrated in U.S. Pat. No. 5,660,064, issued to Ecker et al.
In order to provide an illustration of how the prior art double-locking mechanisms generally operate, the prior art structure of U.S. Pat. No. 4,509,346 is shown as xe2x80x9cPrior Artxe2x80x9d herein as FIG. 2. As depicted in FIG. 2 and described in the Szczepanek patent, xe2x80x9cThe unintentional movement of the bolt into its double-locking position is prevented by providing a restraining means a spring loaded pin [element number 27 in the patent""s drawings]xe2x80x94that operates against the casing and the bolt to resiliently urge the bolt against the latch and against the spreading of the action of mating shoulders [24, 25] on the bolt and latch that cause the two to spread apart against the action of the restraining means as the bolt moves forward toward the double-locking position and the shoulders engage.xe2x80x9d The elements of FIG. 2 are designated with the identical numbers provided in the Szczepanek patent except they are primed.
The double-locking mechanism of the present invention is provided for shackles of the type having a pawl-and-ratchet mechanism, including a spring biased pivotal ratchet pawl that couples a pivotal ratchet jaw arm with a shackle casing, and further includes a bolt for providing engagement with the pawl to prevent the coupled jaw from pivoting in either direction. The improvement includes a pivot slide mechanism in the handcuff or shackle casing which not only permits pivotal movement of a selected one of either the pawl or the bolt about a pivotal axis toward and away from the jaw arm, but also permits this selected one of the pawl or bolt to have limited displacement transversely of its pivot axis. When the selected one of the pawl or bolt is engaged and pulled by a connecting member from a first lock position to a second lock position, the pawl is caused to engage a stop for retaining the pawl in a double locked position. In other words, either the pawl or the bolt may be provided with this pivot slide mechanism whereby when the pawl or bolt so provided is displaced transversely from its pivotal axis, this displacement will cause the pawl to engage a stop within the shackle casing to retain the pawl in the double locked position.
In addition, the bolt is spring biased and dimensioned whereby the bolt is biased from a first bolt position to a second bolt position to thereby engage and retain the pawl in the double locked position against the stop upon the selected one of the pawl or the bolt being displaced to the aforedescribed second lock position. Accordingly, the bolt is spring biased to displace and hold the pawl from disengaging from its double locked position so that the jaw arm cannot be compressed to a further closed position whereby the individual being handcuffed could be injured.
The pivot slide mechanism may be comprised of a pivot pin which is fixed in the handcuff or shackle casing and received in a guide slot in the selected one of the pawl or the bolt for limited lateral displacement. As an alternative, the pivot slide mechanism may be comprised of a pivot pin which is fixed in the selected one of the pawl or the bolt and the extended ends of the pivot pin are permitted to slide in corresponding transverse slots provided on the inside of the casing. When the pivot slide mechanism is provided on the pawl, then the connecting member used to displace the pawl as permitted by the pivot slide mechanism is the jaw arm itself of the handcuff or shackle. In other words, the handcuff is quickly and easily double locked by merely pulling the main body or casing of the cuff casing whereby the jaw arm of the cuff engages the wrist or ankle of the person being shackled and thereby causes the locking arm to displace the pawl and double lock the shackle.
In addition, a pawl spring is provided in the casing and is biased against the pawl to return the pawl to the first lock position when the bolt is displaced from the second bolt position to the first bolt position during unlocking of the cuff with a key. The bolt may either be slidably or pivotally received within the shackle casing and is spring biased such that it is urged to displace toward the pawl.
In an alternative embodiment of the present invention, the pivot slide mechanism may be provided on the bolt instead of the pawl and the connecting member engages the bolt and extends to the exterior of the shackle casing for hand engagement. In this embodiment, the connecting member would typically include the shackle chain extending from and between the cuff shackle casings. Thus, after the cuff is initially applied to the person being detained, the cuff is then easily double locked by merely pulling the shackle chain against a spring bias away from the shackle casing to cause the bolt to displace from its first bolt position to the second bolt position for retaining the pawl in its double locked position.